Exploiting Time Diversity to Improve Block Spread OFDM in a Multipath Environment

2007 Third International Conference on Wireless and Mobile Communications (ICWMC'07)

Lowe

2007

This paper presents a study into different angles for the New spread matrix developed for BSOFDM. It varies the angles for the matrix to develop different constellation schemes which are useful in overcoming the frequency selective channels which are encountered in mobile communication systems. Previously it has been discussed that this new matrix (the rotation matrix) has some advantages over Hadamard and the rotated Hadamard matrix in certain channels. This paper presents a study of varies angles with this new matrix over the UWB channels CM1 to CM4. Disciplines Physical Sciences and Mathematics Publication Details

Section: System Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Study of Different Angles for the New Spread Matrix for BSOFDM in UWB Channels

2007 Third International Conference on Wireless and Mobile Communications (ICWMC'07)

Lowe

2007

“…Primarily this new spreading matrix is used in what has been described as Block Spread OFDM (BSOFDM), which is when the full set of subcarriers are divided into smaller blocks and using spreading matrices to spread the data across these blocks so to achieve frequency diversity across frequency selective channels [2] [3] and [4]. The BOFDM channel model is shown in Figure 1.…”

Section: System Descriptionmentioning

confidence: 99%

Higher order rotation spreading matrix for block spread OFDM

2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications

Lowe

2007

This paper continues the work on the new Rotation matrix developed for BSOFDM which showed improvement in frequency selective channels such as the UWB IEEE defined CM1 to CM4 and overall system performance. This paper presents a method by which higher order Rotation matrix can be derived and simulation results are used to show that the higher order Rotation matrix outperforms the Hadamard matrix in frequency selective channels. KeywordsRotation spreading matrix, BSOFDM, Frequency selective channel Disciplines Physical Sciences and Mathematics

“…This will ensure in a dispersive frequency selective channel the data is statistically less likely to become corrupted and studies and simulations have shown this to be correct. The spreading matrices are generally used to increase the correlation between the transmitted symbols after the transmission has occurred [5], [6] and [7]. Unlike adaptive modulation schemes where depending on the system, a higher order modulation scheme is used to retransmit the data, this scheme utilizes spreading matrices to increase the correlation between the symbols, rather than retransmitting.…”

Section: Introductionmentioning

confidence: 99%

New Higher Order Rotation Spreading Matrix for BSOFDM

The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007)

2007

Previously a new matrix called the Rotation spreading matrix was proposed for Block Spread OFDM which had advantages over other well known spreading matrices such as the Hadamard in frequency selective channels such the UWB channels. Then a new paper discussed a method to expand this Rotation spreading matrix into higher order allowing the system BSOFDM to achieve higher order matrices which still showed excellent orthogonal properties which can be used in these frequency selective channels. This work is continued on the Rotation spreading matrix and this paper presents another method to expand the Rotation spreading matrix based on Complete Complementary Sets of Sequences which the authors have shown to have excellent properties in higher order matrices. This paper discusses the new method and presents a comparison between the two mentioned methods. ABSTRACT Previously a new matrix called the Rotation spreading matrix was proposed for Block Spread OFDM which had advantages over other well known spreading matrices such as the Hadamard in frequency selective channels such the UWB channels. Then a new paper discussed a method to expand this Rotation spreading matrix into higher order allowing the system BSOFDM to achieve higher order matrices which still showed excellent orthogonal properties which can be used in these frequency selective channels. This work is continued on the Rotation spreading matrix and this paper presents another method to expand the Rotation spreading matrix based on Complete Complementary Sets of Sequences which the authors have shown to have excellent properties in higher order matrices. This paper discusses the new method and presents a comparison between the two mentioned methods. 1